Differences Between Promises and Async/Await

Here’s a detailed comparison:

Promises

1. A promise signifies a process that is guaranteed to complete.
2. Promises can exist in one of three states: pending, resolved, or rejected.
3. When promises are chained with .then(), the execution continues after the callback function is added.
4. Error handling is performed using .then() and .catch().
5. Chaining promises can often be complex and difficult to comprehend.
6. Debugging can become challenging when dealing with multiple promise chains.
7. Promises can be employed in scenarios requiring chaining of multiple promises.

Async/Await

1. Async/await serves as syntactic sugar for promises, making asynchronous code appear more synchronous.
2. Async functions do not possess states; they return a promise that can either be resolved or rejected.
3. The await keyword pauses the execution of the function until the promise resolves, causing subsequent calls to wait until completion.
4. Errors can be caught using a try-catch block.
5. The flow of promises is clearer and easier to read with async/await compared to traditional promises.
6. Debugging is simplified with async/await.
7. The await keyword can be applied to individual promises or used with Promise.all() to handle multiple promises concurrently.

In the video "JavaScript Promises vs Async Await EXPLAINED (in 5 minutes)", the distinctions between these two concepts are discussed succinctly, providing a visual aid to enhance understanding.

Should You Choose Promises or Async/Await?

This question often arises among developers, as both options have their use cases in JavaScript coding. If one asynchronous function relies on another, using await is advisable to ensure proper execution order, as it blocks the code until the promise is resolved. Conversely, if you don't require blocking behavior, you can invoke async functions without await, such as in the case of push notifications where you may not need to check the delivery status immediately.

When dealing with multiple asynchronous functions that can execute simultaneously, you can leverage Promise.all([promise1, promise2]) to run them in parallel. Utilizing async/await can greatly simplify the understanding of asynchronous processes. It offers a cleaner code structure compared to promise chaining, making debugging more manageable, especially in complex applications with many microservices.

Async/await presents asynchronous code in a manner that resembles synchronous code, enhancing readability. Handling errors in promises typically requires the addition of a .catch() method, while async/await can be integrated within a try-catch block seamlessly.